this is what i wanted to see:

In practice, kits are paid off after about 18 months and subsequent electricity is free to the new owner.

here? grids are going to be more efficient on a production level, but only better on a cost level if they end up socialized. we can take that jump to the best of both approaches if we want to do it. in some places, it's happening. i don't know how likely that is in africa, but considering they're using kerosene i'd have to question it.

http://www.scientificamerican.com/article.cfm?id=pay-as-you-go-solar-energy